A final word: "or when you fuck up something"
You can use
carajo as a singular word of cursing, and is comparable to saying "Damn!" in English when something doesn't go your way.
I looked it up, and it means something more akin to "Hell", though it's connotation in English equivalency of cursing vocabulary has it's use mirroring that of using the phrase "damn", or more accurately, "Damn you to hell".